The invention relates generally to fluid dispensing nozzles, and more particularly to nozzles for extruding visco-elastic fluidic materials into filaments useable for producing non-woven materials and for depositing adhesives, and methods therefor.
Non-woven materials are known generally and used widely, for example as substrates, which are laminated in the manufacture of a variety of bodily fluid absorbing hygienic articles, and for many other applications. Non-woven materials are formed generally by extruding visco-elastic fluidic materials, like polypropolene or polyethylene or some other polymer, from nozzles into fibers or filaments, which are deposited and combined overlappingly onto an underlying screen or other substrate where the filaments are adhered together, sometimes with an adhesive as is known.
Prior art filament extruding nozzles suitable for non-woven applications generally draw a visco-elastic fluidic material in either continuous or discrete flows from an orifice with a relatively high velocity converging gas like air dispensed concentrically thereabout. U.S. Pat. No. 3,920,362 issued on Nov. 18, 1975, entitled "Filament Forming Apparatus With Sweep Fluid Channel Surrounding Spinning Needle" for example discloses a nozzle having a converging gas passage with a primary orifice and a needle protruding concentrically therein in spaced relation to interior walls of the passage. A drawing gas flowing convergently through the passage between the walls thereof and the needle sweeps liquid from a spin-off tip thereof thus drawing the liquid through the primary orifice and forming continuous or discrete filaments, depending on the liquid supply rate. A plurality of secondary discrete discharge orifices disposed about the primary orifice direct converging secondary gas flows toward the filament. The converging secondary gas flows may contain catalysts for curing or otherwise affecting the filament, and/or may be oriented to impart twist or to further stretch the filament.
The extruding nozzles of the type disclosed in U.S. Pat. No. 3,920,362 and most other extruding nozzles require precision machining operations for the manufacture thereof, and are thus relatively costly. Concentrically configured extruding nozzles of the type disclosed in U.S. Pat. No. 3,920,362 are also relatively bulky, and cannot be fabricated into high density arrays, which are increasingly desirable for many applications, particularly non-woven manufacturing operations. Concentrically configured nozzles also require relatively large amounts of gas to draw the filaments, and are thus relatively inefficient. This is true whether the drawing gas flows in a continuous sheath or in multiple discrete flows arranged concentrically about the drawn fluid. Converging the drawing air flow toward the liquid, as in U.S. Pat. No. 3,920,362, further reduces the drawing efficiency since a component of the converging air flow transverse to the liquid flow direction has no affect on drawing. Also, most sweeping or drawing gases are supplied from compressed air systems, which generally have limited supply pressure capacities, and are costly to operate and maintain. It is therefore generally desirable to reduce consumption of the drawing gas.
The present invention is drawn toward advancements in the art of nozzles for extruding visco-elastic fluidic materials, useable for producing non-woven materials and depositing adhesives, and methods therefor.
It is an object of the invention to provide novel nozzles for extruding visco-elastic fluidic materials and methods therefor that overcome problems in the art.
It is another object of the invention to provide novel nozzles for extruding visco-elastic fluidic materials, useable for producing non-woven materials and depositing adhesives, and methods therefor that are economical.
It is another object of the invention to provide novel nozzles and methods therefor for extruding visco-elastic fluidic materials relatively efficiently, and more particularly extrusion nozzles that require less drawing gas or air.
It is a further object of the invention to provide novel nozzles for extruding visco-elastic fluidic materials efficiently, useable for producing non-woven materials and depositing adhesives, and methods therefor, and more particularly extruding nozzles having relatively reduced size, and extruding nozzles that may be manufactured economically and in relatively high density arrays without merging visco-elastic flows drawn from adjacent visco-elastic orifices prior to formation of the visco-elastic filaments.
It is a more particular object of the invention to provide novel nozzles for extruding visco-elastic fluidic materials and methods therefor comprising dispensing a plurality of first and second fluids from a plurality of first and second orifices to form corresponding first and second adjacent fluid flows. The first fluid flows are drawn and attenuated by not more than one corresponding second fluid flow at a second velocity greater than a first velocity of the first fluid flow to form corresponding first fluid filaments, which are preferably relatively continuous and vacillated chaotically. The corresponding first and second fluid flows are spaced as closely as possible to maximize filament drawing efficiency, and adjacent first fluid orifices are spaced sufficiently apart to prevent merging of the first fluid flows prior filament formation.
These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators.